The Beagle Diary was later used to write Darwin's famous book 'Voyage of the Beagle' (1839). The narrative of the surveying voyages of His Majesty's Ships Adventure and Beagle between the years 1826 and 1836. Darwin describes each day of the voyage, some in intimate detail, during the Beagle's circumnavigation of the globe.

21st August 1836

Mid Atlantic
We crossed the Equator.

Syms Covington Journal

Crossed the Equatorial Line, at a quarter after 10 o'clock, Sunday the 21st with a fine breeze from the Southward and Eastward, which we have had since or from Pernambuco.